Sonos Arc and 7.1 Downmix to 5.1

I have the Sonos Arc full setup with LG C1 and Apple TV. Weird and bad stuff going on with sound as well. Someone mentioned a known bug with Apple TV with 15.3 but 15.4 is supposed to solve (no Atmos only MC 7.1). Have mine as pass through, bitstream and atmos on. 

depends how you are testing it too. When I found this problem I was testing it using a test disc that plays isolated beeping sounds through each channel one by one (it's a calibration tool so you can make sure the channels work and the volume is correct) and two of the channels were clearly not working, the disc was playing audio but the Sonos speakers made no sound. I also tested it a second time using a game - games also works well for testing because you can make a static sound come out of any channel you want by moving around.

Testing this problem using a movie or music or anything that you can't control won't work  because you have no idea what you're supposed to hear and just accept it as fact. Testing surround audio in a movie or music is only possible if you have a 2nd system to compare against 

Are they?

Sorry to quote an old post, but this issue is ancient now, its quite laughable that they said they were working on it, which is well over a year ago. They dont even acknowledge the issue or respond to posts on the subject anymore to give an update. 

Issue or no issue, they should respond.

Hi @ledzep1 

Sonos does not currently support 7.1 channel McLPCM audio, though, as you see above, some users report experiencing no problems with it.

The official line is, “this is a feature we are currently working on, however; we do not have any further information to share with you at this time. Rest assured, we will address this in a forthcoming update.”

Once we have made our position clear - that we have never supported this format, therefore it not working isn’t an issue or a bug, but a forth-coming feature that we haven’t yet released or advertised - it seems needless to repeatedly answer all references to it. When we do release the feature, we’ll update the relevant threads on the forum - closed or not. Incidentally, I don’t think “working on” literally means there’s someone coding away at it right now, but that it is in a list of work that needs to be done and is quite likely to be repeatedly pushed down that list by actual bugs/issues that show up, or by upcoming projects/features that require a lot of concerted effort.

If Sonos doesn’t support 7.1 LPCM why/how does it report it in the app? I don’t think anybody is deliberately trying to send an unsupported format to the speaker, or waiting for it to be added as a feature. Rather it appears that the speaker is either asking for it incorrectly, or it is being sent incorrectly over eARC by LG OLED TVs. Either way this is a problem not a missing feature albeit maybe not of Sonos making. The frustration in these threads is more to do with the lack of clarity and uncertainty of whether it is impacting the sound in any way. I’m inclined to suspect that a hardware issue has been found hence the silence for so long and the repositioning of this as a feature but would be happy to be corrected.

Hi @ste_ms 

I think you’re confusing “support” with “play” and “recognise”. What we mean by “not supporting”, in this instance, is that if it doesn’t work, and you call our technical support team to try and get it working, we won’t be able to assist. Not out of spite, or hardware issues, but because the software to downmix 7.1 to 5.1 hasn’t yet been fully written/tested/implemented.

We cannot tell you that the 7.1 stream will be impacted in a certain way if it has not been fully explored and tested. No information is often (if not always) better than wrong information. We have not mentioned 7.1 support in any way, other than to respond to direct customer queries. The acknowledgement that we will be supporting 7.1 at all in the future is, frankly, more information than we usually put out about up-coming features.

If a digital audio stream can be transported to an audio device quickly enough, then the only thing that would get in the way of it playing is lack of software, and CPU power to run the software (and LPCM doesn’t take much). For example, all our Home Theatre products - even those that are discontinued - recently gained the ability to play DTS streams, simply by us adding software to let them do so.

I hope this helps.

So I do appreciate you responding but the issue here is that nobody is sending a 7.1 signal and worrying about whether it will play or whether Sonos supports it. I am not seeing anybody asking for 7.1 support to be added as a feature in any of the many threads discussing this issue as what would be the point on a system that physically tops out at 5.1?

The issues are all associated with playing back 5.1 tracks that are being reported as 7.1 in the sonos app. For me this happens with an Apple TV 4K and a PS5. Either the TV is converting 5.1 to 7.1 incorrectly (in my case an LG CX), or the TV is sending the correct 5.1 track but the wrong metadata to the Beam, or the Beam is incorrectly reporting received 5.1 tracks as 7.1 in the app.

I’d be happy to submit diagnostics etc if it would help but I think there is a bug here somewhere, not a missing feature.

Hi @ste_ms 

I think you should read the first post on this thread again. 7.1 downmixing to 5.1 is the topic of this thread, regardless of what anyone else has been saying. The post from @ledzep1 that I was responding to specifically was also along these lines.

The point of supporting 7.1 on a system that only has 5.1 (apart from when it’s 5.1.2) is that instead of throwing away channels to play the stream, channels are amalgamated instead (down-mixed). Side-channel effects would, presumably, be mixed to both front and rear channels on that side, for example.

No bugs. If you play a 5.1 track and it arrives at the Arc as a 7.1 track, then, as you have said, your source device or TV has either up-mixed it to 7.1 or has changed the descriptor on the stream for some reason (I can’t think of any valid reasons to do this). Either way, it’s not something we, Sonos, can address.

I recommend you get in touch with LG or Sony support.

I think you should read the posts on this thread again and the many others by the person you replied to discussing the exact issue I outlined. Your reply seems unnecessarily dismissive and condescending. I and many others are only asking for some feedback on an issue that I acknowledged may not be on Sonos but I suspect probably is to some extent as it spans multiple hardware sources from different manufacturers.

@ste_ms I don’t believe he is dismissing the issue. I think he is saying that it is less of a Sonos issue and more of an LG issue. It’s no coincidence that 99% of the users experiencing this issue have LG TVs. Have you contacted LG yet?